The invention relates to an agitator, particularly one of the impeller shape, consisting of a hub with a plurality of radially extending agitator arms for rotation in an agitator or mixing vessel.
Agitators are used for the mixing of substances that tend to material build-up, incrustation and/or incipient polymerization and which can change from the liquid state into the disperse or pasty state. It is essential to prevent material build-up, incrustation and/or incipient polymerization on the agitator so as not to impair its mixing function. Routine cleaning operations should leave the agitator residue free. Therefore, the number of gaps between adjacent components of the agitator should be minimized.
Agitators of different shapes are shown in the prior art. The anchor shape, the impeller shape and the propeller shape are some of the well-known designs. Depending upon the design of the agitator, the surface finish, enamelled or bright, and the size of the agitator vessel, the agitators can be of the single-part type or must be of the multi-part type. The type of agitator also depends upon the possible or economical diameter of the agitator vessel cover. An agitator vessel with a cover diameter equal to the vessel diameter will permit installation of a single-part agitator. If the agitator has a reduced diameter, the installation opening and the vessel cover can also be reduced with reference to the vessel diameter. However, some processes require a larger diameter agitator so that the cover diameter finally selected requires the use of a multi-part agitator.